It’s hard to tell whether it’s too fast or too slow - you have to find the speed you’re comfortable with on your own.
“Too fast” can mean you learn so many new items that you’re drowning in reviews - they keep piling up and you can’t get them under control (for instance because real life doesn’t leave you enough time for that).
“Too fast” can also mean you don’t take enough time to memorize your mnemonics. Your short term memory might be enough to get them to Guru but then they might drop back to apprentice because you forgot them. If this happens with too many items you will, again, drown in reviews.
“Too fast” can mean you theoretically are able to keep your reviews in check but it wears you out mentally such that after 20 levels you just burn out and take a break for a year - after which you don’t remember much.
In any case I don’t think you’re going “too slow”… 2-3 levels per month seems like a rather tight pace (though I’m at a similar pace atm).
Btw: If you care about a bit of friendly competition you can also join the manly race 